5.1: Page Types, Anatomy & Control Structure

5.1 Page Types, Anatomy & Control Structure

In Microsoft Dynamics 365 Business Central, Pages represent the visual presentation and interaction tier of the application. Every user interaction—from viewing customer lists and entering sales orders to configuring system setup and interacting with AI Copilot prompts—occurs through a page object. For the MB-820 certification exam, developers must master the comprehensive taxonomy of page types, understand the structural containers of page definitions, configure modern action ribbons, and apply page properties that govern searchability, performance, and data manipulation.

1. Comprehensive Taxonomy of Page Types

The AL programming language provides a rich set of page types specified via the PageType object property. The selected PageType dictates how the Web Client renders the user interface, how records are displayed, and which interactive features are available.

Exam Watch: On the MB-820 exam, pay close attention to the distinction between StandardDialog, NavigatePage, and PromptDialog. A multi-step wizard guiding an administrator through setup steps must use NavigatePage. Quick parameter entry dialogs use StandardDialog. Generative AI prompt-and-response flows use PromptDialog.

2. Structural Containers: Layout and Areas

A page object definition in AL contains two mandatory top-level blocks: layout and actions (plus an optional views block). The layout block defines the visual data controls presented on the screen, organized into dedicated areas:

1. area(Content)

The primary container where the core business data controls reside:

• On a Card page, area(Content) contains one or more group() containers that render as collapsible FastTabs (e.g., General, Invoicing, Shipping).
• On a List page, area(Content) contains a single repeater() control that renders the multi-record data grid.
• On a Document page, area(Content) contains header group() FastTabs and embedded part() controls representing line subforms.

2. area(FactBoxes)

The secondary container located on the right side of the screen (the FactBox pane) that provides contextual, real-time insights regarding the selected record without requiring the user to navigate away:

• Custom FactBoxes: Declared using part(Name; PageIdentifier) bound to the active record via the SubPageLink property.
• System FactBoxes: Declared using systempart(Name; SystemPartType):
  • systempart(Links; Links): Displays attached URL hyperlinks and document shortcuts.
  • systempart(Notes; Notes): Displays internal user notes and record commentary.
  • systempart(MyNotes; MyNotes): Displays legacy user-specific personal notes.

3. area(Prompting)

Introduced for AI Copilot experiences (PageType = PromptDialog). It hosts input prompt fields where users specify natural language instructions and displays AI-generated output previews.

4. area(RoleCenter)

The root layout container exclusively utilized when PageType = RoleCenter. It hosts modular part pages including HeadlinePart, CardPart (Cues and Activities), and embedded operational list parts.

3. Actions Container & The Modern Promoted Action Bar

The actions block defines the ribbon commands, buttons, and menus available to the user. Actions are organized into standard functional action areas:

The Modern Promoted Actions Architecture (area(Promoted))

In modern Business Central development, the legacy method of promoting actions (using Promoted = true; PromotedCategory = Process; on individual action blocks) is obsolete. Developers must define an area(Promoted) container within the actions block and reference actions using actionref controls grouped inside group(Category_...):

actions
{
    area(Processing)
    {
        action(PostInvoice)
        {
            ApplicationArea = All;
            Caption = 'Post';
            ToolTip = 'Finalize and post the sales invoice.';
            Image = PostOrder;

            trigger OnAction()
            begin
                Codeunit.Run(Codeunit::"Sales-Post", Rec);
            end;
        }
    }
    area(Promoted)
    {
        group(Category_Process)
        {
            Caption = 'Process';
            
            actionref(PostInvoice_Promoted; PostInvoice)
            {
            }
        }
    }
}

4. Essential Page Properties and Discoverability

Page properties configure execution rules, search visibility, and data integrity:

Discoverability: UsageCategory and ApplicationArea

To make a page discoverable in the Tell Me search box (keyboard shortcut: Alt+Q), two properties must be configured simultaneously:

1. ApplicationArea: Must match an active application area enabled in the user's tenant (commonly All, Basic, Suite).
2. UsageCategory: Dictates the Tell Me search classification. Valid values include:
   • Lists: Tabular master and transactional lists.
   • Tasks: Operational worksheets and task cards.
   • Administration: Setup and configuration pages.
   • Documents: Transactional headers and orders.
   • History: Posted documents and historical archives.
   • ReportsAndAnalysis: Analytical reports and financial queries.
   • None: Excludes the page from Tell Me search (default).

Exam Rule: Subpages (ListPart, CardPart) and FactBoxes must never specify UsageCategory (leave as None). Setting a UsageCategory on a subpart causes compilation warnings and clutters Tell Me with unusable partial pages.

Data Manipulation and Concurrency Properties

5. Complete AL Page Definition Example

The following code demonstrates a robust AL Card page definition illustrating properties, layout areas, FastTabs, FactBoxes, and modern promoted actions:

page 50100 "Equipment Card"
{
    PageType = Card;
    SourceTable = "Equipment Item";
    Caption = 'Equipment Card';
    UsageCategory = None;
    RefreshOnActivate = true;

    layout
    {
        area(Content)
        {
            group(General)
            {
                Caption = 'General';
                field("No."; Rec."No.")
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies the unique identifier for the equipment.';
                    Importance = Promoted;
                }
                field(Description; Rec.Description)
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies a descriptive title for the equipment.';
                    Importance = Promoted;
                }
                field("Serial No."; Rec."Serial No.")
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies the manufacturer serial number.';
                }
                field(Status; Rec.Status)
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies the current operational readiness status.';
                    Importance = Promoted;
                }
            }
            group(Maintenance)
            {
                Caption = 'Maintenance & Service';
                Importance = Additional;
                field("Last Service Date"; Rec."Last Service Date")
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies the date of the most recent service inspection.';
                }
                field("Warranty Expiry Date"; Rec."Warranty Expiry Date")
                {
                    ApplicationArea = All;
                    ToolTip = 'Specifies when the factory warranty coverage ends.';
                }
            }
        }
        area(FactBoxes)
        {
            part(EquipmentPicture; "Equipment Picture FactBox")
            {
                ApplicationArea = All;
                SubPageLink = "No." = field("No.");
            }
            systempart(Links; Links)
            {
                ApplicationArea = RecordLinks;
            }
            systempart(Notes; Notes)
            {
                ApplicationArea = Notes;
            }
        }
    }

    actions
    {
        area(Processing)
        {
            action(ScheduleMaintenance)
            {
                ApplicationArea = All;
                Caption = 'Schedule Maintenance';
                ToolTip = 'Create a new maintenance work order for this equipment.';
                Image = ServiceOrder;

                trigger OnAction()
                var
                    MaintMgmt: Codeunit "Equipment Maintenance Mgmt";
                begin
                    MaintMgmt.CreateWorkOrder(Rec);
                end;
            }
        }
        area(Promoted)
        {
            group(Category_Process)
            {
                Caption = 'Process';
                actionref(ScheduleMaintenance_Promoted; ScheduleMaintenance)
                {
                }
            }
        }
    }
}